This cat was a feral tom that had lived in the Nat'l Forest, that it took me months to calm down enough to pet it or hand feed it. Calm as can be now and sometimes a pita with all his meowing wanting a treat, but the feral instinct never goes away.
Cats figure their 'owners' are so inept at hunting, they have to try to teach us and even do it for us. Cats kill for the fun of it--I watched this one catch a mouse in the driveway one night and keep it just alive enough that it would still try to squirm away when cat threw it up in the air--went on for 20 minutes or so till I finally took the nasty thing away and threw it in the trash bin.